It sounds weird to me. Is the rule located at a proper .htaccess, at a proper folder?
It should be like this:
RewriteEngine On
RewriteRule ^pagelog(/)?$ pagelog.php [L]
I tried it and it worked as it is supposed to.
Just for an inspiration: you may consider using a more general rule, something like:
RewriteEngine On
RewriteRule ^([a-z0-9-]*)(/)?$ $1.php [QSA,L]
I hope it helped.